1. Field of the Invention
The present invention relates to an olefin/cycloolefin/alkylstyrene copolymer, and more particularly to a functionalized olefin/cycloolefin/alkylstyrene copolymer which have enhanced properties such as good adhesion to a substrate and good compatibility with other polymers.
2. Description of the Prior Art
Non-functionalized cycloolefin copolymer (COC) are of high transparency and hardness and of low density. Furthermore, they are virtually chemically and moisture inert and are highly resistant to heat deformation. However, since non-functionalized COCs have non-polar molecular structure, they have poor adhesion to the substrate and poor compatibility with most other polymers.
Many researchers have drawn their attentions to synthesize functionalized cycloolefin copolymer in order to improve the adhesion properties and compatibility with other polymers. For example, Kreuder et al. in U.S. Pat. No. 5,756,623 have disclosed an ene-functionalized COC, which includes polymerized units of at least one cycloolefin, polymerized units of at least one olefin containing at least one double bond, polymerized units of at least alpha olefins, and polymerized units which possess at least two electron-withdrawing groups which are carbonyl or nitrile.
In JP 5279412, an unsaturated copolymer is obtained by compolymerizing C2-C12 alpha olefin and a cyclic olefin containing alkylidene group or alkenyl group. Then, the unsaturated copolymer is oxidized with a peracid. Thus, the double bond of the alkylidene group or alkenyl group in the unsaturated copolymer is oxidized and epoxy group and/or OH group is introduced to the double bond.
In JP 5279413, an unsaturated copolymer similar to JP 5279412 is first obtained. Then, the unsaturated copolymer is reacted with a halogen or a hydrogen halide. As a result, the halogen group is introduced to the double bond in the unsaturated copolymer.
In JP 5287015, an unsaturated copolymer similar to JP 5279412 is first obtained. Then, amino group is introduced to the double bond in the unsaturated copolymer.
Chung et al. in U.S. Pat. No. 5,543,484 have disclosed a functionalized xcex1-olefin/para-alkylstyrene copolymer.
First, xcex1-olefin and para-alkylstyrene are copolymerized. The incorporation of p-alkylstyrene into the xcex1-olefin polymer results in the generation of benzylic protons, which are readily available for many chemical reactions, thereby introducing functional groups at the benzylic position under mild reaction conditions. Then, the olefin/p-alkylstyrene copolymer is functionalized by the functionalization of benzylic protons in p-alkylstyrene units. Such functionalization leads to improvement in the physical properties of the original olefin polymers.
An object of the present invention is to provide an olefin/cycloolefin/alkylstyrene copolymer, and more particularly a functionalized olefin/cycloolefin/alkylstyrene copolymer. By the functionalization of benzylic protons in alkylstyrene units, the olefin/cycloolefin/alkylstyrene copolymer can have good adhesion to the substrate and good compatibility with other polymers.
To achieve the above-mentioned object, the olefin/cycloolefin/alkylstyrene copolymer of the present invention includes the following repeating units: 
wherein
R1 and R2 are independently selected from the group consisting of hydrogen, alkyl, and primary and secondary haloalkyl,
X can be the same or different and is selected from the group consisting of (1) hydrogen, (2) a functional group, (3) a polymer moiety, (4) an alkali or alkaline earth metal, and (5) mixtures thereof, wherein the functional group is selected from a group containing halogen, oxygen, sulfur, silicon, nitrogen, carbon, phosphorus, and mixtures thereof; 
wherein
a is an integer from 0 to 3,
R3, R4, R5, R6, R8, R9, R10, and R11 can be the same or different and are selected from the group consisting of hydrogen, halogen, C1-10 alkyl, and haloalkyl and
R12 and R13 can be the same or different and are selected from the group consisting of hydrogen, halogen, C1-10 alkyl, haloalkyl, aryl, haloaryl, alcohol, ester, and acid, or R12 and R13 can be bonded together to form formula (III) 
wherein
R14 and R15 can be the same or different and are selected from the group consisting of hydrogen, halogen, C1-10 alkyl, and haloalkyl and
b is an integer from 3 to 5; and 
wherein
Rxe2x80x2 is C1 to C18 linear and branched alkyl, and most preferably Rxe2x80x2 is C1 to C5 primary or secondary alkyl.
The feature of the present invention is to introduce an alkylstyrene unit to an olefin/cycloolefin copolymer in order to obtain an olefin/cycloolefin/alkylstyrene copolymer. It is the first an olefin/cycloolefin/alkylstyrene copolymer is synthesized.
The incorporation of the alkylstyrene unit into the olefin/cycloolefin copolymer results in the generation of benzylic protons, which are readily available for many chemical reactions. Many functional groups can be introduced to the benzylic position under mild reaction conditions. By the functionalization, the adhesion to the substrate and the compatibility with other polymers can be improved compared with the non-functionalized olefin/cycloolefin/alkylstyrene copolymer.
The general process for preparing the olefin/cycloolefin/alkylstyrene copolymer of the present invention will be described below.
First, monomers (A), (B), (C), and optionally (D) are copolymerized to form an olefin/cycloolefin/alkylstyrene copolymer.
Monomer (A) is in an amount of 0.1-50 molt and is an alkylstyrene represented by formula (I) 
R1 and R2 are independently selected from the group consisting of hydrogen, alkyl, and primary and secondary haloalkyl. Preferably, R1 and R2 are independently selected from the group consisting of hydrogen, C1 to C5 alkyl, and C1 to C5 primary and secondary haloalkyl.
Monomer (3) is in an amount of 1-99 molt and is an cycloolefin represented by formula (II) 
wherein
a is an integer from 0 to 3,
R3, R4, R5, R6, R8, R9, R10, and R11 can be the same or different and are selected from the group consisting of hydrogen, halogen, C1-10 alkyl, and haloalkyl and
R12 and R13 can be the same or different and are selected from the group consisting of hydrogen, halogen, C1-10 alkyl, haloalkyl, aryl, haloaryl, alcohol, ester, and acid, or R12 and R13 can be bonded together to form formula (III) 
R14 and R15 can be the same or different and are selected from the group consisting of hydrogen, halogen, C1-10 alkyl, and haloalkyl and
b is an integer from 3 to 5.
Monomer (C) is in an amount of 0.1-98.9 mol % and is ethylene, an C3-20 xcex1-olefin, or mixtures thereof.
Monomer (D) is in an amount of 0-50 mol % and is a non-conjugated diene.
The olefin/cycloolefin/alkylstyrene copolymer obtained above contains an alkylstyrene unit represented by 
wherein
R1 and R2 are independently selected from the group consisting of hydrogen, alkyl, and primary and secondary haloalkyl.
Then, the alkyltyrene unit-containing copolymer is subjected to halogenation to obtain a cycloolefin copolymer containing the repeating unit (vi) At (vi) 
wherein X contains halogen.
The halogenated copolymer is very reative on the halogen group and is readily to undergo various reaction to form other functional groups. For example, the halogenated copolymer can be reacted with a nucleophile selected from a compound containing oxygen, sulfur, silicon, nitrogen, carbon, and phosphorus to obtain a cycloolefin copolymer containing the following repeating unit (vi) 
wherein X contains an element selected from the group consisting of oxygen, sulfur, silicon, nitrogen, carbon, and phosphorus.
When some of the X groups contain oxygen, the oxygen-containing group can be alkoxides, phenoxides or carboxylates.
When some of the X groups contain sulfur, the sulfur-containing group can be thiolates, thiophenolates, thioethers, thiocarboxylates, dithiocarboxylates, thioureas, dithiocarbamates, xanthates or thiocyanates.
When some of the X groups contain silicon, the silicon-containing group can be silanes or halosilanes.
When some of the X groups contain nitrogen, the nitrogen-containing group can be amides, amines, carbazoles, phthalimides, pyridines, maleimides or cyanates.
Some of the X groups can also be functionalized to malonates, cyanides, phosphine, phosphite, or CR31, wherein each R31 is an organic radical.
In addition, the benzylic protons of the olefin/cycloolefin/alkylstyrene copolymer is readily to undergo grafting of a polymer moiety. Also, a halogenated olefin/cycloolefin/alkylstyrene copolymer is readily to undergo grafting of a polymer moiety.
The grafting techniques can be classified into xe2x80x9cgraft-fromxe2x80x9d and xe2x80x9cgraft-onxe2x80x9d. Graft-from technique involves the reaction of an olefin/cycloolefin/alkylstyrene copolymer and a monomer via anionic polymerization, cationic polymerization, anionic or cationic ring-open polymerization, or free radical polymerization. A xe2x80x9cgraft-fromxe2x80x9d anionic polymerization is as follows (only the alkylstyrene unit is shown for simplification): 
The reaction of a halogenated (such as brominated) olefin/cycloolefin/alkylstyrene copolymer with a monomer via cationic polymerization is as follows (only the alkylstyrene unit is shown for simplification): 
The reaction of a halogenated (such as brominated) olefin/cycloolefin/alkylstyrene copolymer with a monomer via free radical polymerization is as follows (only the alkylstyrene unit is shown for simplification): 
The xe2x80x9cgraft-onxe2x80x9d technique involves the reaction of a functionalized olefin/cycloolefin/alkylstyrene copolymer and a polymer which can react with the functional group of such an olefin/cycloolefin/alkylstyrene copolymer, such that the polymer bonds to the functionalized olefin/cycloolefin/alkylstyrene copolymer and grafting is achieved.
In the repeating unit (i), when the X group contains a polymer moiety, the polymer moiety can be polymers and copolymers of anionically polymerizable monomers, cationically polymerizable monomers, anionically and cationically ring-openable monomers, or free radical polymerizable monomers.
Representative examples of the anionically polymerizable monomers include conjugated dienes, vinyl aromatic compounds, vinyl unsaturated amides, acenaphthylene, 9-acrylcarbazole, acrylonitrile, methacrylonitrile, organic isocyanates, acrylates, methacrylates, alkyl acrylates, alkyl methacrylates, glycidyl methacrylates, vinyl pyridines, and mixtures thereof.
Representative examples of the cationically polymerizable monomers include vinyl aromatic compounds, vinyl ethers, N-vinylcarbazole, isobutene, and mixtures thereof.
Representative examples of the ring-openable monomers include cyclic ethers, sulfides, lactones, lactams, N-carboxyanhydrides, cyclic anhydrides, and mixtures thereof.
Representative examples of the free radical polymerizable monomers include vinyl aromatic compounds, conjugated dienes, acrylates, methacrylates, alkyl acrylates, alkyl methacrylates, vinyl acetates, and mixtures thereof.
According to the present invention, if the monomer (D) (a non-conjugated diene) is present for the copolymerization, then an olefin/cycloolefin/alkylstyrene/non-conjugated diene copolymer is obtained. In such a copolymer, there is a residual double bond left, and the double bond is readily available for many chemical reactions. Many functional groups can be introduced to the copolymer via the reaction of the double bond. Thus, the copolymer can be modified according to various requirements.
Preferably, the non-conjugated diene used in the present invention can be a non-conjugated cyclic diene. Suitable non-conjugated cyclic diene can be selected from the group consisting of 
wherein
R21, R22, R23, R24, R25, R26, and R27 can be the same or different and are selected from the group consisting of hydrogen, C1-8 alkyl, C6-14 aromatic group, and C2-15 alkenyl,
m, n, and q can be the same or different and is an integer of 0 to 3.
A respresentative example of such a non-conjugated cyclic diene is 5-ethylidene-2-norbornene (ENB).
The reaction of the residual double bond of the olefin/cycloolefin/alkylstyrene/non-conjugated diene is described below. The olefin/cycloolefin/alkylstyrene/non-conjugated diene copolymer can be reacted with a compound which is reactive with a double bond such that the residual double bond of the non-conjugated diene is functionalized to form a group selected from epoxy, halogen, ether, alcohol, sulfate, borane, borate, aldehyde, and ketone.
When the residual double bond of the non-conjugated diene is functionalized to form epoxy, the epoxidated copolymer can further be subjected to a ring-opening reaction. By means of the ring-opening reaction of the epoxy group of the epoxidated copolymer, the copolymer can contain xe2x80x94R, xe2x80x94OH, xe2x80x94OR, or xe2x80x94NH2 after the ring-opening reaction, wherein R is selected from the group consisting of alkyl, complete halogenated alkyl, and partial halogenated alkyl.
According to the present invention, the monomers (A), (B), (C), and optionally (D) can be conducted in the presence of a catalyst composition including a single-site catalyst, preferably a metallocene catalyst, and an activating cocatalyst. Preferred metallocenes include zirconocene and titanocene coordination compounds with single or double cyclopentadienyl derivatives which form the constrained ligand geometry. The activating cocatalyst can be aluminoxane such as methyl aluminoxane (MAO), a trialkyl aluminum, a dialkyl aluminum halide, a salt of an inert and non-coordinating anion, or a mixture thereof. Preferably, the catalyst composition includes a metallocene and methyl aluminoxane.
The following examples are intended to illustrate the process and the advantages of the present invention more fully without limiting its scope, since numerous modifications and variations will be apparent to those skilled in the art.